ADLINK HSL-AI16AO2-M-VV/-AV - Manual (Page 18)

Introducing HSL 5
modules at fixed scanning period and keeps the most updated
I/O status information on the SRAM. You may read and write
the data in the 32 KB SRAM on HSL master card through the
PCI or PMC bus. You can easily read/write the most updated I/
O information and never worry with the HSL protocol.
1.1.3 HSL Applications
HSL as a Distributed PLC
The distributed PLC is an important system in the field of indus-
try automation. Via communication modules, such as RS232,
RS485, PLC also performs distributed control. The traditional
architecture of distributed PLC application is shown in Figure
1.2. In this setup, the MPC (Monitoring PC) takes over as the
medium for data transmission from field to MIS.
Figure 1-2: Traditional distributed PLC architecture
With the development of communication technology and popular-
ity of networking, networking modules with Ethernet interface
became available. This improvement evolved as shown in the
architecture below. The medium character of the MPC was
replaced.
RS-485